Description DetailsDescription: Max-Planck-Institute for Chemistry, Atmospheric Chemistry Division, P.O Box 3060, 55020 Mainz, Germany. Only a few previous observations of very low
O3 mixing ratios in the upper troposphere are available. The aim of this study was to examine the rich MOZAIC data set for more. Flights
with at least 25 4 s averaged mixing ratios less than 8 ppbv at pressures lower than
500 hPa measured using commercial aircraft within the MOZAIC project have been analysed. There
are eleven flights that fulfil these conditions (excluding artefacts as discussed below),
representing about 0.001% of all measurements during the analysed period August
1994-December 1997. The low O3
events occurred over Southeast Asia, Africa, Brazil and the sea area 200
km east of Florida (US) and were all likely to be associated with transport of air
masses from tropical sea areas. These low mixing ratio events occur in the upper troposphere
during periods with generally low mixing ratios. They are not only found over sea, but also
over land at pressure levels as low as 179 hPa. It could well b...

Description DetailsDescription: University of Thessaly, Department of Agriculture School of Plant Production and Agricultural Environment, Volos, Greece. The maximum deepening rate per cyclone track is determined by the maximum height drop at the center of the cyclone (500-hPa low) on the basis of all the 6-h successive steps in its life cycle. The geopotential height gradient is calculated over the entire low area and the calculation continued with the variation of the gradient in the successive steps. The maximum intensification rate per cyclone is then determined as the maximum increase of the gradient in the life cycle. Maximum deepening rate for the 500-hPa cyclones in the area does not exceed, on average, 12 gpm/6 h. Maximum intensification which is 1.4 gpm/100 Km*6 h on average, occurs in the early stages of the cyclone's life cycle. This on the average happens approximately 9 h after the first time the low is detected. At the gulf of Genoa and the Adriatic Sea, cyclones usually show the maximum intensification after the maximum deepening. At Turkey's cyclogenesis area, however, this order is reversed. The spatial distributions of maximum inten...

Description DetailsDescription: Istituto Nazionale di Oceanografia e di Geofisica Sperimentale–OGS, Borgo Grotta Gigante 42/C, I-34010 Sgonico–Trieste, Italy. This paper presents an
analysis of sound speed distribution in the Mediterranean Sea based on
climatological temperature and salinity data. In the upper layers, propagation
is characterised by upward refraction in winter and an acoustic channel in
summer. The seasonal cycle of the Mediterranean and the presence of gyres and
fronts create a wide range of spatial and temporal variabilities, with relevant
differences between the western and eastern basins. It is shown that the
analysis of a climatological data set can help in defining regions suitable for
successful monitoring by means of acoustic tomography. Empirical Orthogonal
Functions (EOF) decomposition on the profiles, performed on the seasonal cycle
for some selected areas, demonstrates that two modes account for more than 98%
of the variability of the climatological distribution. Reduced order EOF
analysis is able to correctly represent sound speed profiles within each zone,
thus providing the a priori knowledge f...

Description DetailsDescription: Grup de Meteorologia, Universitat de les Illes Balears, Mallorca, Spain. A large number of high impact cyclones all over the Mediterranean basin have
been reported on the data base of the MEDEX project (http://medex.inm.uib.es). A
numerical study on the impacts and interactions of baroclinic and diabatic
factors is carried out through a PV-based system of prognostic equations for 11
intense MEDEX cyclone episodes occurred in different zones of the basin
(Western, Central and Eastern Mediterranean). The main aim of the study is to
investigate the possible similarities and differences among the selected cases
of the relative weight of the considered cyclogenetic factors on the cyclone
evolutions as function of cyclone type and geographical area. A crucial role of
the baroclinicity over the Mediterranean zone is obtained in most of the cases.
A certain distinction can be also established in terms of the cyclogenesis areas
(Africa, Mediterranean Sea, and Alpine region), and between west-central and
eastern Mediterranean basins. It is generally observed that the considered
baroclinic and diabatic factors coopera...

Description DetailsDescription: Institut de Géologie, Université de Fribourg, Pérolles, 1700 Fribourg, Switzerland. Ever since coral reefs exist, changing environmental
conditions have periodically led to their decline. However, within the perspective of geological time-spans,
corals have always managed to re-install themselves.
Today, human activity has enhanced stress factors and
added new ones that cause a rapid and (on the human
time-scale) irreversible decline of many reef ecosystems. The reasons for the disturbance of these complex
communities are multiple, but global warming is a key
factor. As a result, coral reefs lose their vital role of protecting
coastal areas from flooding and storm impact
and of creating habitats for numerous marine organisms. In this short article, natural and anthropogenically
induced stress factors are discussed, and measures for
mitigating or stopping coral-reef decline are proposed....

Description DetailsDescription: Laboratoire de Modélisation de la Chimie Atmosphérique, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland. This paper reports on Long Range Transport (LRT) of ozone and related species
over the North Atlantic ocean and its impact on Europe. Measurements of
NO2 and O3 columns from the GOME and MOPITT satellite instruments are first used
in conjunction with the GEOS-CHEM global model of transport and tropospheric
chemistry to identify the major events of LRT that reach Europe over the
course of the summer 2000. Model simulations are then used to examine surface
O3 observations at a European mountain site and O3 vertical profiles over
several European cities to quantify the impact of the LRT events on the
European ozone distributions. Over the course of summer 2000, we identified
nine major episodes of pollution transport between North America and Europe,
which are in majority associated with WCB/post-frontal outflow (7 events) and
zonal transport (2 events). We find that on average three episodes occur per
month with the strongest ones being in J...

Excerpt DetailsDwight's Journal of Music mentions a Herr Grube in connection with Vassar, and indeed Vassar's General catalogue of the officers and graduates of Vassar college lists a Charles Grube among officers of instruction for the period 1885 to 1894. However, i...

Description DetailsDescription: LISA, UMR 7583, Universités Paris 7 et 12, Créteil, France. The potentiality of dust particles to mix with sulphate over Tropical Africa
and the Atlantic Ocean is investigated by combining a meso-scale
meteorological model with a dust production model and an SO2 emission
database. This mixing process study is based on a qualitative approach where
the reactivity of dust is estimated from its calcite content, which is the
main mineral known to be reactive with sulphur species. We are presenting a
1-month simulation (January 1993). Our results show that the regions
Northern Egypt and Libya (NEL), Western Sahara (WS) and Sahel (S) are the
major sources of dust plumes. The simulated dust loading is in agreement
with the measured data close to the African coasts. The Mediterranean and
Maghreb regions are highly influenced by European sources of sulphate, for
which the simulated concentrations are consistent with the observed trends.
This simplified study identifies two zones that favour the mixing process
between dust and sulphate: 1. the Eastern Mediterranean basin due to the
concomitance of high con...

Description DetailsDescription: Institute of Atmospheric Science, School of Earth and Environment, University of Leeds, UK. We use the new GLOMAP model of global aerosol microphysics to investigate the sensitivity of modelled sulfate and
sea salt aerosol properties to uncertainties in the driving microphysical processes and compare these
uncertainties with those associated with aerosol and precursor gas emissions. Overall, we conclude that
uncertainties in microphysical processes have a larger effect on global condensation nuclei (CN) and cloud
condensation nuclei (CCN) concentrations than uncertainties in present-day sulfur emissions. Our simulations
suggest that uncertainties in predicted sulfate and sea salt CCN abundances due to poorly constrained
microphysical processes are likely to be of a similar magnitude to long-term changes in CCN due to changes in
anthropogenic emissions. A microphysical treatment of the global sulfate aerosol allows the uncertainty in
climate-relevant aerosol properties to be attributed to specific processes in a way that has not been possible
with simpler aerosol schemes. In particular we conclude that: (1) chan...

Description DetailsDescription: LSCE, Orme des Merisiers, Bat 709, CE Saclay, 91191 Gif-sur-Yvette Cedex, France. A detailed study on the temporal variability of compounds important in controlling
aerosol chemical composition was performed during a one-month experiment conducted
during summer 2000 at a background site on Crete, in the Eastern Mediterranean Sea.
Contribution of different aerosol sources in the Eastern Mediterranean Basin could be
investigated at this location since the site is influenced by a wide range of air masses
originating mainly in Europe and Africa. Chemical apportionment was performed for
various air mass origins and showed a strong impact of anthropogenic emissions in the
Turkey and Central Europe sectors, with black carbon (BC) and non-sea-salt sulfate
(nss-SO4) concentrations being almost a factor of two higher than observed in the Eastern and
Western Europe sectors. High levels of non-sea-salt calcium (nss-Ca) were associated
with air masses from Africa but also from Central Turkey. Evidence was found that BC
calculation based on light absorbance during dust events was...

Description DetailsDescription: University of Wyoming, Geology and Geophysics Department, 1000 E. University Ave., Laramie, WY, 82071, USA. We present 3-D images of ocean finestructure from a unique industry-collected
3-D multichannel seismic dataset from the Gulf of Mexico that includes
expendable bathythermograpgh casts for both swaths. 2-D processing reveals
strong laterally continuous reflectors throughout the upper ~800 m as
well as a few weaker but still distinct reflectors as deep as ~1100 m.
Two bright reflections are traced across the 225-m-wide swath to produce
reflector surface images that show the 3-D structure of internal waves. We
show that the orientation of internal wave crests can be obtained by
calculating the orientations of contours of reflector relief. Preliminary 3-D
processing further illustrates the potential of 3-D seismic data in
interpreting images of oceanic features such as internal wave strains. This
work demonstrates the viability of imaging oceanic finestructure in 3-D and
shows that, beyond simply providing a way to see what oceanic finestructure
looks like, quantitative information such as the spatial ori...

Description DetailsDescription: Istituto di Scienze dell’Atmosfera e del Clima, ISAC – CNR, Via Fosso del Cavaliere, 100, 00133 Roma, Italy. The one-year (2001) record of aerosol data from the space borne Moderate
Resolution Imaging Spectroradiometer (MODIS) was analyzed focusing on the
Mediterranean region. The MODIS aerosol optical thickness standard product
(AOT at 550 nm) provided over both land and ocean was employed to evaluate
the seasonal and spatial variability of the atmospheric particulate over the
region. Expected accuracy of the MODIS AOT is (±0.05±0.2×AOT)
over land and (±0.03±0.05×AOT) over ocean. The
seasonal analysis revealed a significant AOT variability all over the
region, with minimum values in Winter (AOT<0.15) and maximum in Summer
(AOT>0.2). The spatial variability is also found to be considerable,
particularly over land. The impact of some major urban sites and
industrialized areas is detectable. For the sole Mediterranean basin, a
method (aerosol mask) was implemented to separate the contribution of
maritime, continental and desert dust aerosol to the total AOT. Input of
both continental and desert dust particle...

Description DetailsDescription: Forschungszentrum Jülich, Inst. for Energy and Climate Research, IEK-7, Jülich, Germany. The frequency of occurrence of cirrus clouds and contrails, their life
time, ice crystal size spectra and thus their radiative properties
depend strongly on the ambient distribution of the relative humidity
with respect to ice (RHice). Ice clouds do not form below a certain
supersaturation and both cirrus and contrails need at least saturation
conditions to persist over a longer period. Under subsaturated
conditions, cirrus and contrails should dissipate. During the
mid-latitude aircraft experiment CONCERT 2008 (CONtrail and Cirrus
ExpeRimenT), RHice and ice crystals were measured in cirrus and
contrails. Here, we present results from 2.3/1.7 h of
observation in cirrus/contrails during 6 flights. Thin and subvisible
cirrus with contrails embedded therein have been detected frequently
in a subsaturated environment. Nevertheless, ice crystals up to radii
of 50 Μm and larger, but with low number densities were
often observed inside the contrails as well as in...

Description DetailsDescription: Laboratoire de Météorologie Physique, CNRS, Université Blaise Pascal, UMR6016, Clermont-Ferrand, France. Within the frame of the European Aerosol Cloud Climate and Air Quality Interactions
(EUCAARI) project the Météo-France aircraft ATR-42 performed 22 research flights,
over central Europe and the North Sea during the intensive observation period in
May 2008. For the campaign, the ATR-42 was equipped in order to study aerosol
physical, chemical and optical properties, as well as cloud microphysics. During
the campaign, continental air masses from Eastern and Western Europe were
encountered, along with polar and Scandinavian air masses. For the 22 research
flights, retroplume analyses along the flight tracks were performed with
FLEXPART in order to classify air masses into five sectors of origin which
allows for a qualitative evaluation of emission influence on the respective air parcel.
In the polluted boundary layer (BL), typical concentrations of particles with diameters
larger than 10 nm (N10) are of the order of 5000–6000 cm−3, whereas N10
conc...

Description DetailsDescription: Department of Earth Sciences, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden. Fault scarps that extend up to 155 km and have
offsets of tens of meters at the surface are present in
the northern parts of Finland, Norway and Sweden. These
fault scarps are inferred to have formed during
earthquakes with magnitudes up to 8 at the time of the
last deglaciation. The Pärvie fault system
represents the largest earthquake so far documented in
northern Scandinavia, both in terms of its length and
its calculated magnitude. It is also the longest known
glacially induced fault in the world. Present-day
microearthquakes occur along the length of the fault
scarp on the eastern side of the scarp, in general
agreement with an east dipping main fault. In the
central section of the fault, where there is a number of
subsidiary faults east of the main fault, it has been
unclear how the earthquakes relate to the faults mapped
at the surface. A seismic profile across the Pärvie
Fault system acquired...

Description DetailsDescription: CSIRO Marine and Atmospheric Research, Aspendale, Vic, Australia. Emissions of biomass-burning aerosols from the Indonesian region are known to
vary in response to rainfall anomalies associated with the El Niño Southern
Oscillation (ENSO). However, the effects of these rainfall anomalies on
regional aerosol burdens and radiative forcing have not been investigated. In
this study, we simulate the effects of ENSO-related changes in (1) emissions
and (2) rainfall and circulation on the radiative forcing of Indonesian
biomass-burning aerosols. We find that rainfall and circulation anomalies, as
well as emissions, contribute substantially to the direct and first indirect
radiative effects.

We compare two experiments that are performed with the CSIRO-Mk3.6
atmospheric global climate model (GCM). The first experiment (AMIP) consists
of a pair of runs that respectively represent El Niño and La Niña
conditions. In these runs, the distribution of aerosols is simulated under
the influence of realistic Indonesian biomass-burning aerosol emissions and
sea surface temperatures (SSTs) for 1997 (El Niño) and ...

Description DetailsDescription: This paper presents a mechanism to explain
the observed formation of a surface temperature minimum at tidal fronts in shelf
seas. Tidal fronts mark the boundary between water which is kept vertically
mixed by fast tidal currents and water which stratifies in summer. The fronts
are associated with strong horizontal surface gradients of several water
properties, including temperature. In the early studies of tidal fronts, a
minimum in surface temperature was occasionally observed between the cool
surface waters on the mixed side of the front and the warm surface waters on the
stratified side. It was suggested that this was caused by upwelling of deep
water at the front. In this paper we describe an alternative and simpler
explanation based on the local balance of heating and stirring. The net heat
flux into the sea in spring and early summer is greater on the mixed side of the
front than on the stratified side. This happens because the heat loss mechanism
is dependent on sea surface temperature and stratified waters, having a higher
surface temperature, lose more heat. The stratified water near the front
th...